Subtitling

Captions are text versions of the word. Captions allow Web audio and video content to be accessible to those who do not have access to audio. Although captioning is primarily intended for those who can not hear the sound, it is useful to those who can not hear the audio (for various reasons and not just because of a hearing impairment) and those who do not feel comfortable in the language spoken in the audio.

Recommendations for Web accessibility that specify the subtitles should be:

• Synchronized - the content of the subtitles to be displayed when the sound is heard.
• Equivalent - content of the subtitles should be equivalent to the words pronounced.
• Accessible - the subtitle should be accessible and available to read for those who need it.

On the Web, synchronized captions and equivalents should be provided as soon as audio is present. ou Windows Media Player mais elle peut également s'appliquer aux technologies telles que Flash, Shockwave , Java ou quand le contenu audio est une partie d'une présentation multimédia. This recommendation applies to audio and video played in media players like Quicktime, RealPlayer or Windows Media Player but it can also be applied to technologies such as Flash, Shockwave, Java or when the audio is part of a multimedia presentation.

Subtitles on demand or inlaid

Most people are familiar with the captioning on demand (closed captionning), a technical presentation of the subtitles when they are desired by the user. All television sets with screens of 13 inches and must contain the device to display the subtitles. Closed captioning of most television programs pre-recorded is now a legal requirement in the United States. Subtitling in television is used by millions of people who are deaf or hard of hearing. Millions more people use it in class (school) or in noisy environments such as bars, restaurants and airports. As the average age of the population increases, the number of people with hearing loss also increases. According to U.S. government figures, one in five has a functional limitation in hearing. Due to the increasing need to access subtitles, many live broadcasts (such as news and sporting events), DVD and VHS programs now offer closed captioning on demand.

Closed captioning on television is very limited in its formatting because the visual appearance and the location of the subtitles on the screen are determined by the decoder built into the television. You can get more information on closed captioning on television by consulting the FAQs .

Subtitles embedded include the same text as the subtitles on demand, but the subtitles here are a permanent part of the image and can not usually be disabled. It's like watching the subtitling of foreign language films. DVDs use a form of subtitling for specific display subtitles. The subtitles are not embedded decoded by the TV. They are part of the video. This technique allows more control over the location, size, color, font and synchronization of subtitles.

Videos for the Web, the subtitles can be embedded or at the request, or both. A technique for embedded subtitling is the addition of subtitles directly into video. This requires a video editing or encoding program that allows you to overlay subtitles on video. The subtitles appear to anyone watching the video and can not be disabled. This gives you complete control over how the subtitles appear, but can be very time consuming and costly to produce. The method of subtitling for the most common subtitle audio and video on the Web is to use the functionality of media players to display the subtitles inside or outside of the video or audio.

Audio description

The audio description provides additional information on what is visible on the screen. This allows video content to be accessible to persons with visual impairments. Although it is not commonly used in television and film, audio description is becoming increasingly popular. The audio descriptions are useful if the Web content provides visual information not available through the audio alone. An example of audio description for something you've probably seen is below. Can you imagine what is described?

Listen to an audio description in an MP3 format (152 kb)

If Web video is created with accessibility in mind, then the audio descriptions are often unnecessary as the visuals in the video are described in the main audio.

Text transcript

The text transcript is an important point of access multimedia content on the Web. The verbatim transcript allows anyone who can not access the audio or video content on the Web to read text instead. A verbatim transcript is not necessarily an exact recovery of the words of his video. It may contain descriptions, explanations or comments that are beneficial to understanding. Text transcripts allow deafblind to get the content of the video by using a Braille and other devices. For most Web video, subtitles and text transcript must be provided. For content that is audio only, then a text transcript is usually sufficient.

A verbatim transcript gives a textual content that can then be accessed by anyone. It also allows multimedia content to be indexable by search engines. Users of screen readers may prefer the verbatim transcript also listen to the audio multimedia. Most users proficient in the use of screen readers paramètent their assistive technology to read at a speed much faster than the playback speed of normal people. This allows users of screen readers to access the verbatim transcript of the video and get the same content in less time than if they listened to the audio.

Glossary of subtitling and technologies

Web, multimedia technologies are key technologies Microsoft Windows Media Player, Apple QuickTime, RealNetworks RealPlayer and Macromedia Flash. Unfortunately, there is no mechanism fully standardized captioning for all of these technologies. Each media player has a special technique for closed captioning. Some technologies and conditions subtitling in different media players.

SMIL (Synchronized Multimedia Integration Language)

pour contrôler la mise en page et la présentation des éléments visuels et sonores. SMIL est utilisé pour contrôler l'affichage, le positionnement et la synchronisation des sous-titres par rapport au multimédia audio/vidéo. A language based on standards used by Quicktime and RealPlayer to control layout and presentation of visual and sound elements. SMIL is used to control the display, positioning and timing of the subtitles from the multimedia audio / video. si vous utilisez RealPlayer . The subtitles are stored in a text file (a new track) if you use Quicktime or a RealText file if you use RealPlayer.

SAMI (Synchronized Accessible Media Interchange)

Microsoft technology to add subtitles in Windows Media Player. A SAMI file contains the text displayed in the subtitles and information for synchronizing the display of subtitles with the multimedia presentation.

Text track

Quicktime uses a file to create a track that stores text subtitles and timing information.

RealText

pour stocker les sous-titres et les informations de synchronisation. RealPlayer uses RealText file to store subtitles and timing information.

Magpie

est un logiciel gratuit pour créer des fichiers de sous-titres qui peuvent être utilisés par les lecteurs multimédia. Developed by CPB / WGBH National Center for Accessible Media (NCAM), Magpie is a free software to create files of subtitles that can be used by media players.

Hi-Caption

qui permet la création de sous-titres pour les lecteurs multimédia. Hi-Caption is HiSoftware software that allows creation of captions for media players.